package tui

import (
	"os"
	"os/exec"
	"strings"
	"time"

	"github.com/atotto/clipboard"
	tea "github.com/charmbracelet/bubbletea"

	"github.com/lerko/nib/internal/carddata"
	"github.com/lerko/nib/internal/db"
)

type entitiesLoadedMsg struct {
	entities []*db.Entity
}

type entityCreatedMsg struct {
	entity *db.Entity
}

type entityDeletedMsg struct {
	id string
}

type entityUpdatedMsg struct {
	entity *db.Entity
	action string
}

type entityPromotedMsg struct {
	id       string
	cardType db.CardType
}

type entityDemotedMsg struct {
	id string
}

type entityCopiedMsg struct{}

type entityAbsorbedMsg struct {
	targetID string
}

type absorbSourcesLoadedMsg struct {
	targetID string
	entities []*db.Entity
}

type stepsPersistedMsg struct{}

type templateCopiedMsg struct{}

type tagsLoadedMsg struct {
	tags []db.TagCount
}

type statusClearMsg struct{ seq int }

type editorFinishedMsg struct {
	err error
}

type errMsg struct {
	err error
}

func loadEntities(store *db.Store, params db.ListParams) tea.Cmd {
	return func() tea.Msg {
		entities, err := store.List(params)
		if err != nil {
			return errMsg{err}
		}
		return entitiesLoadedMsg{entities}
	}
}

func createEntity(store *db.Store, e *db.Entity) tea.Cmd {
	return func() tea.Msg {
		if err := store.Create(e); err != nil {
			return errMsg{err}
		}
		return entityCreatedMsg{e}
	}
}

func deleteEntity(store *db.Store, id string) tea.Cmd {
	return func() tea.Msg {
		if _, err := store.SoftDelete(id); err != nil {
			return errMsg{err}
		}
		return entityDeletedMsg{id}
	}
}

func toggleTodo(store *db.Store, e *db.Entity) tea.Cmd {
	return func() tea.Msg {
		var update db.EntityUpdate
		if e.CompletedAt == nil {
			now := time.Now().UTC()
			update = db.EntityUpdate{CompletedAt: &now}
		} else {
			update = db.EntityUpdate{ClearCompleted: true}
		}

		if err := store.Update(e.ID, &update); err != nil {
			return errMsg{err}
		}
		updated, err := store.Get(e.ID)
		if err != nil {
			return errMsg{err}
		}
		action := "completed"
		if e.CompletedAt != nil {
			action = "reopened"
		}
		return entityUpdatedMsg{updated, action}
	}
}

func pinEntity(store *db.Store, e *db.Entity) tea.Cmd {
	return func() tea.Msg {
		newPinned := !e.Pinned
		update := db.EntityUpdate{Pinned: &newPinned}
		if err := store.Update(e.ID, &update); err != nil {
			return errMsg{err}
		}
		updated, err := store.Get(e.ID)
		if err != nil {
			return errMsg{err}
		}
		action := "pinned"
		if !newPinned {
			action = "unpinned"
		}
		return entityUpdatedMsg{updated, action}
	}
}

func promoteEntity(store *db.Store, id string, ct db.CardType, body string) tea.Cmd {
	return func() tea.Msg {
		cd := carddata.GenerateCardData(ct, body)
		if err := store.Promote(id, ct, cd); err != nil {
			return errMsg{err}
		}
		return entityPromotedMsg{id, ct}
	}
}

func demoteEntity(store *db.Store, id string) tea.Cmd {
	return func() tea.Msg {
		if err := store.Demote(id); err != nil {
			return errMsg{err}
		}
		return entityDemotedMsg{id}
	}
}

func copyToClipboard(store *db.Store, e *db.Entity) tea.Cmd {
	return func() tea.Msg {
		if err := clipboard.WriteAll(e.Body); err != nil {
			return errMsg{err}
		}
		if err := store.IncrementUse(e.ID); err != nil {
			return errMsg{err}
		}
		return entityCopiedMsg{}
	}
}

func loadTags(store *db.Store) tea.Cmd {
	return func() tea.Msg {
		tags, err := store.ListTags(false)
		if err != nil {
			return errMsg{err}
		}
		return tagsLoadedMsg{tags}
	}
}

func editInEditor(store *db.Store, e *db.Entity) tea.Cmd {
	editorEnv := os.Getenv("EDITOR")
	if editorEnv == "" {
		editorEnv = os.Getenv("VISUAL")
	}
	if editorEnv == "" {
		editorEnv = "vi"
	}
	parts := strings.Fields(editorEnv)
	editor, editorArgs := parts[0], parts[1:]

	f, err := os.CreateTemp("", "nib-edit-*.md")
	if err != nil {
		return func() tea.Msg { return errMsg{err} }
	}
	if _, err := f.WriteString(e.Body); err != nil {
		f.Close()
		os.Remove(f.Name())
		return func() tea.Msg { return errMsg{err} }
	}
	f.Close()

	c := exec.Command(editor, append(editorArgs, f.Name())...)
	return tea.ExecProcess(c, func(err error) tea.Msg {
		defer os.Remove(f.Name())
		if err != nil {
			return editorFinishedMsg{err}
		}

		content, readErr := os.ReadFile(f.Name())
		if readErr != nil {
			return editorFinishedMsg{readErr}
		}

		newBody := string(content)
		if newBody == e.Body {
			return editorFinishedMsg{nil}
		}

		update := db.EntityUpdate{Body: &newBody}
		if updateErr := store.Update(e.ID, &update); updateErr != nil {
			return editorFinishedMsg{updateErr}
		}

		return editorFinishedMsg{nil}
	})
}

func loadAbsorbSources(store *db.Store, targetID string) tea.Cmd {
	return func() tea.Msg {
		entities, err := store.List(db.DefaultListParams())
		if err != nil {
			return errMsg{err}
		}
		return absorbSourcesLoadedMsg{targetID, entities}
	}
}

func absorbEntity(store *db.Store, targetID, sourceID string) tea.Cmd {
	return func() tea.Msg {
		if err := store.Absorb(targetID, sourceID); err != nil {
			return errMsg{err}
		}
		return entityAbsorbedMsg{targetID}
	}
}

func persistSteps(store *db.Store, entityID string, stepsJSON string) tea.Cmd {
	return func() tea.Msg {
		update := db.EntityUpdate{CardData: &stepsJSON}
		if err := store.Update(entityID, &update); err != nil {
			return errMsg{err}
		}
		return stepsPersistedMsg{}
	}
}

func copyResolved(store *db.Store, entityID string, resolved string) tea.Cmd {
	return func() tea.Msg {
		if err := clipboard.WriteAll(resolved); err != nil {
			return errMsg{err}
		}
		if err := store.IncrementUse(entityID); err != nil {
			return errMsg{err}
		}
		return templateCopiedMsg{}
	}
}

func clearStatusAfter(d time.Duration, seq int) tea.Cmd {
	return tea.Tick(d, func(time.Time) tea.Msg {
		return statusClearMsg{seq: seq}
	})
}