package main

import (
	"encoding/json"
	"errors"
	"strconv"

	"srs.epita.fr/fic-server/libfic"
)

var ApiThemesRouting = map[string]DispatchFunction{
	"GET":    listTheme,
	"POST":   creationTheme,
	"DELETE": deletionTheme,
}

type uploadedTheme struct {
	Name string
}

type uploadedExercice struct {
	Title     string
	Statement string
	Hint      string
	Depend    *int
	Gain      int
	VideoURI  string
}

func getTheme(args []string) (fic.Theme, error) {
	if tid, err := strconv.Atoi(string(args[0])); err != nil {
		return fic.Theme{}, err
	} else {
		return fic.GetTheme(tid)
	}
}

func getExercice(args []string) (fic.Exercice, error) {
	if theme, err := getTheme(args); err != nil {
		return fic.Exercice{}, err
	} else if eid, err := strconv.Atoi(string(args[1])); err != nil {
		return fic.Exercice{}, err
	} else {
		return theme.GetExercice(eid)
	}
}

func listTheme(args []string, body []byte) (interface{}, error) {
	if len(args) == 2 {
		return getExercice(args)
	} else if len(args) == 1 {
		return getTheme(args)
	} else if len(args) == 0 {
		// List all themes
		return fic.GetThemes()
	} else {
		return nil, nil
	}
}

func creationTheme(args []string, body []byte) (interface{}, error) {
	if len(args) == 1 {
		if theme, err := getTheme(args); err != nil {
			return nil, err
		} else {
			// Create a new exercice
			var ue uploadedExercice
			if err := json.Unmarshal(body, &ue); err != nil {
				return nil, err
			}

			if len(ue.Title) == 0 {
				return nil, errors.New("Title not filled")
			}

			var depend *fic.Exercice = nil
			if ue.Depend != nil {
				if d, err := fic.GetExercice(*ue.Depend); err != nil {
					return nil, err
				} else {
					depend = &d
				}
			}

			return theme.AddExercice(ue.Title, ue.Statement, ue.Hint, depend, ue.Gain, ue.VideoURI)
		}
	} else if len(args) == 0 {
		// Create a new theme
		var ut uploadedTheme
		if err := json.Unmarshal(body, &ut); err != nil {
			return nil, err
		}

		if len(ut.Name) == 0 {
			return nil, errors.New("Theme's name not filled")
		}

		return fic.CreateTheme(ut.Name)
	} else {
		return nil, nil
	}
}

func deletionTheme(args []string, body []byte) (interface{}, error) {
	if len(args) == 2 {
		if exercice, err := getExercice(args); err != nil {
			return nil, err
		} else {
			return exercice.Delete()
		}
	} else if len(args) == 1 {
		if theme, err := getTheme(args); err != nil {
			return nil, err
		} else {
			return theme.Delete()
		}
	} else {
		return nil, nil
	}
}