module Harvest.TaskAPI
    exposing
        ( Task
        , tasksDecoder
        , taskDecoder
        , getAllTasks
        , getTask
        , createTask
        , deleteTask
        , updateTask
        , reactivateTask
        , TaskAssignment
        , taskAssignmentsDecoder
        , taskAssignmentDecoder
        , getTasksAssignedToProject
        , getTaskAssignment
        , assignTaskToAProject
        , createNewTaskAndAssignItToProject
        , removeTaskFromProject
        , updateTaskAssignment
        )

{-| Warpper around Harvest Task API

# Task
@docs Task

# Task API
@docs getAllTasks, getTask, createTask, deleteTask, updateTask, reactivateTask

# Task decoders
@docs tasksDecoder, taskDecoder

# TaskAssignment
@docs TaskAssignment

# TaskAssignment API
@docs getTasksAssignedToProject, getTaskAssignment, assignTaskToAProject, createNewTaskAndAssignItToProject, removeTaskFromProject, updateTaskAssignment

# TaskAssignment decoders
@docs taskAssignmentsDecoder, taskAssignmentDecoder
-}

import Date exposing (Date)
import Json.Encode as JE
import Json.Decode exposing (..)
import Json.Decode.Pipeline exposing (..)
import Json.Decode.Extra exposing (date)
import Json.Encode.Extra as JEE exposing (maybe)
import Http exposing (..)
import Dict exposing (Dict)


{-| Representation of a task.
-}
type alias Task =
    { id : Int
    , name : String
    , billableByDefault : Bool
    , isDefault : Bool
    , defaultHourlyRate : Float
    , deactivated : Bool
    , createdAt : Maybe Date
    , updatedAt : Maybe Date
    }


{-| Representation of a taskassignment.
-}
type alias TaskAssignment =
    { id : Int
    , projectId : Int
    , taskId : Int
    , billable : Bool
    , deactivated : Bool
    , hourlyRate : Float
    , budget : Maybe Float
    , estimate : Maybe Float
    , createdAt : Date
    , updatedAt : Date
    }



{- decoders -}


{-| Decode a JSON list of tasks into a `List Task`.
-}
tasksDecoder : Decoder (List Task)
tasksDecoder =
    list (field "task" taskDecoder)


{-| Decode a JSON task into a `Task`.
-}
taskDecoder : Decoder Task
taskDecoder =
    decode Task
        |> required "id" int
        |> required "name" string
        |> required "billable_by_default" bool
        |> required "is_default" bool
        |> required "default_hourly_rate" float
        |> required "deactivated" bool
        |> required "created_at" (nullable date)
        |> required "updated_at" (nullable date)


{-| Decode a JSON list of task assignments into a `List TaskAssignment`.
-}
taskAssignmentsDecoder : Decoder (List TaskAssignment)
taskAssignmentsDecoder =
    list (field "task_assignment" taskAssignmentDecoder)


{-| Decode a JSON task assignment into a `TaskAssignment`.
-}
taskAssignmentDecoder : Decoder TaskAssignment
taskAssignmentDecoder =
    decode TaskAssignment
        |> required "id" int
        |> required "project_id" int
        |> required "task_id" int
        |> required "billable" bool
        |> required "deactivated" bool
        |> required "hourly_rate" float
        |> required "budget" (nullable float)
        |> required "estimate" (nullable float)
        |> required "created_at" date
        |> required "updated_at" date


{-|
Show All Tasks

Usage:
`getAllTasks accountId token params`

sends a GET request to `https://{accountId}.harvestapp.com/tasks?access_token={token}`

Allowed parameters:

`updated_since` e.g. `updated_since=2015-09-25+18%3A30`
-}
getAllTasks : String -> String -> Dict String String -> Request (List Task)
getAllTasks accountId token params =
    request
        { method = "GET"
        , headers = [ header "Accept" "application/json" ]
        , url = createUrl accountId token params
        , body = emptyBody
        , expect = expectJson tasksDecoder
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Show One Task

Usage:
`getTask accountId taskId token`

sends a GET request to `https://{accountId}.harvestapp.com/tasks/{task_id}?access_token={token}`

Response: `200 OK` if successful
-}
getTask : String -> Int -> String -> Request Task
getTask accountId taskId token =
    request
        { method = "GET"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/tasks/" ++ (toString taskId) ++ "?access_token=" ++ token
        , body = emptyBody
        , expect = expectJson taskDecoder
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Create New Task

Usage:
`createTask accountId token task`

sends a POST request to `https://{accountId}.harvestapp.com/tasks?access_token={token}`

A successful call will return: `201 Created` and the header `Location: /tasks/{new_task_id}`
-}
createTask : String -> String -> Task -> Request String
createTask accountId token task =
    let
        url =
            "https://" ++ accountId ++ ".harvestapp.com/tasks?access_token=" ++ token
    in
        request
            { method = "POST"
            , headers = [ header "Accept" "application/json", header "Content-Type" "application/json" ]
            , url = url
            , body = jsonBody <| encodeTask task
            , expect = expectString
            , timeout = Nothing
            , withCredentials = False
            }


{-|
Archive/Delete A Task

Usage:
`deleteTask accountId taskId token`

sends a DELETE request to `https://{accountId}.harvestapp.com/tasks/{task_id}?access_token={token}`
-}
deleteTask : String -> Int -> String -> Request String
deleteTask accountId taskId token =
    request
        { method = "DELETE"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/tasks/" ++ (toString taskId) ++ "?access_token=" ++ token
        , body = emptyBody
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Update A Task

Usage:
`updateTask accountId task token`

sends a PUT request to `https://{accountId}.harvestapp.com/tasks/{task_id}?access_token={token}`
-}
updateTask : String -> Task -> String -> Request String
updateTask accountId task token =
    request
        { method = "PUT"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/tasks/" ++ (toString task.id) ++ "?access_token=" ++ token
        , body = jsonBody <| encodeTask task
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Reactivate A Task

Usage:
`reactivateTask accountId taskId token`

sends a POST request to `https://{accountId}.harvestapp.com/tasks/{taskId}/activate?access_token={token}`
-}
reactivateTask : String -> Int -> String -> Request String
reactivateTask accountId taskId token =
    request
        { method = "PUT"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/tasks/" ++ (toString taskId) ++ "/activate?access_token=" ++ token
        , body = emptyBody
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }



{- Task assignments -}


{-|
All Assigned Tasks To Project

Usage:
`getTasksAssignedToProject accountId projectId token params`

sends a GET request to `https://{accountId}.harvestapp.com/projects/{project_id}/task_assignments?access_token={token}`

Allowed parameters:

`updated_since` e.g. `updated_since=2010-09-25+18%3A30`
-}
getTasksAssignedToProject : String -> Int -> String -> Dict String String -> Request (List TaskAssignment)
getTasksAssignedToProject accountId projectId token params =
    request
        { method = "GET"
        , headers = [ header "Accept" "application/json" ]
        , url = taskAssignmentUrl accountId projectId token params
        , body = emptyBody
        , expect = expectJson taskAssignmentsDecoder
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Get One Task Assignment

Usage:
`getTaskAssignment accountId projectId assignmentId token`

sends a GET request to `https://{accountId}.harvestapp.com/projects/{PROJECT_ID}/task_assignments/{TASK_ASSIGNMENT_ID}?access_token={token}`

Response: `200 OK` if successful
-}
getTaskAssignment : String -> Int -> Int -> String -> Request TaskAssignment
getTaskAssignment accountId projectId assignmentId token =
    request
        { method = "GET"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString projectId) ++ "task_assignments/" ++ (toString assignmentId) ++ "?access_token=" ++ token
        , body = emptyBody
        , expect = expectJson taskAssignmentDecoder
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Assign Task To A Project

Usage:
`assignTaskToAProject accountId taskId projectId token`

sends a POST request to `https://{accountId}.harvestapp.com/projects/{projectId}/task_assignments?access_token={token}`

Retruns `Location: /projects/{PROJECT_ID}/task_assignments/{NEW_TASK_ASSIGNMENT_ID}`
-}
assignTaskToAProject : String -> Int -> Int -> String -> Request String
assignTaskToAProject accountId taskId projectId token =
    request
        { method = "POST"
        , headers = [ header "Accept" "application/json", header "Content-Type" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString projectId) ++ "/task_assignments?access_token=" ++ token
        , body = jsonBody <| encodeTaskAssignmentId taskId
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Create A New Task And Assign It To A Project

Usage:
`createNewTaskAndAssignItToProject accountId projectId taskName token`

sends a POST request to `https://{accountId}.harvestapp.com/projects/{PROJECT_ID}/task_assignments/add_with_create_new_task?access_token={token}`

Returns `Location: /projects/{PROJECT_ID}/task_assignments/{NEW_TASK_ASSIGNMENT_ID}`
-}
createNewTaskAndAssignItToProject : String -> Int -> String -> String -> Request String
createNewTaskAndAssignItToProject accountId projectId taskName token =
    request
        { method = "POST"
        , headers = [ header "Accept" "application/json", header "Content-Type" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString projectId) ++ "/task_assignments/add_with_create_new_task?access_token=" ++ token
        , body = jsonBody <| encodeTaskName taskName
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Removing A Task From A Project

Usage:
`removeTaskFromProject accountId projectId assignmentId token`

sends a DELETE request to `https://{accountId}.harestapp.com/projects/{projectId}/task_assignments/{assignmentId}?access_token={token}`
-}
removeTaskFromProject : String -> Int -> Int -> String -> Request String
removeTaskFromProject accountId projectId assignmentId token =
    request
        { method = "DELETE"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString projectId) ++ "/task_assignments/" ++ (toString assignmentId) ++ "?access_token=" ++ token
        , body = emptyBody
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }


{-|
Updating A Task Assignment For A Project

Usage:
`updateTaskAssignment accountId assignment token`

sends a PUT request to `https://{accountId}.harvestapp.com/projects/{PROJECT_ID}/task_assignments/{TASK_ASSIGNMENT_ID}?access_token={token}`
-}
updateTaskAssignment : String -> TaskAssignment -> String -> Request String
updateTaskAssignment accountId assignment token =
    request
        { method = "PUT"
        , headers = [ header "Accept" "application/json" ]
        , url = "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString assignment.projectId) ++ "/task_assignments/" ++ (toString assignment.id) ++ "?access_token=" ++ token
        , body = jsonBody <| encodeTaskAssignment assignment
        , expect = expectString
        , timeout = Nothing
        , withCredentials = False
        }



{- helpers -}


encodeTask : Task -> JE.Value
encodeTask p =
    JE.object
        [ ( "task"
          , JE.object
                [ ( "name", JE.string p.name )
                , ( "billable_by_default", JE.bool p.billableByDefault )
                , ( "is_default", JE.bool p.isDefault )
                , ( "default_hourly_rate", JE.float p.defaultHourlyRate )
                , ( "deactivated", JE.bool p.deactivated )
                ]
          )
        ]


encodeTaskAssignment : TaskAssignment -> JE.Value
encodeTaskAssignment assignment =
    JE.object
        [ ( "task_assignment"
          , JE.object
                [ -- ( "name", JE.string assignment.name ) WRONG DOCUMENTATION!!!
                  ( "billable", JE.bool assignment.billable )
                , ( "budget", JEE.maybe JE.float assignment.budget )
                , ( "deactivated", JE.bool assignment.deactivated )
                , ( "hourly_rate", JE.float assignment.hourlyRate )
                ]
          )
        ]


encodeTaskAssignmentId : Int -> JE.Value
encodeTaskAssignmentId taskId =
    JE.object
        [ ( "task"
          , JE.object
                [ ( "id", JE.int taskId ) ]
          )
        ]


encodeTaskName : String -> JE.Value
encodeTaskName name =
    JE.object
        [ ( "task"
          , JE.object
                [ ( "name", JE.string name ) ]
          )
        ]


createUrl : String -> String -> Dict String String -> String
createUrl accountId token params =
    let
        url =
            "https://" ++ accountId ++ ".harvestapp.com/tasks?access_token=" ++ token

        p =
            Dict.foldl (\key val agg -> agg ++ "&" ++ key ++ "=" ++ val) "" params
    in
        url ++ p


taskAssignmentUrl : String -> Int -> String -> Dict String String -> String
taskAssignmentUrl accountId projectId token params =
    let
        url =
            "https://" ++ accountId ++ ".harvestapp.com/projects/" ++ (toString projectId) ++ "/task_assignments?access_token=" ++ token

        p =
            Dict.foldl (\key val agg -> agg ++ "&" ++ key ++ "=" ++ val) "" params
    in
        url ++ p