package views

import (
	"encoding/json"
	"fmt"
	"strings"

	ops "fn-registry/fn_operations"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
	"github.com/lucasdataproyects/devfactory/tui"
)

type historyState int

const (
	historyLoading historyState = iota
	historyList
	historyDetail
)

type historyLoadedMsg []ops.Execution

// HistoryModel shows execution history.
type HistoryModel struct {
	state         historyState
	list          tui.FilteredListModel
	spinner       tui.SpinnerModel
	styles        tui.Styles
	executions    []ops.Execution
	detail        string
	scrollOff     int
	opsDB         *ops.DB
	pipelineNames map[string]string
}

// NewHistoryModel creates a new history view.
func NewHistoryModel(styles tui.Styles, opsDB *ops.DB, names map[string]string) HistoryModel {
	return HistoryModel{
		state:         historyLoading,
		list:          tui.NewFilteredList(nil, "Filter executions..."),
		spinner:       tui.NewSpinner("Loading history..."),
		styles:        styles,
		opsDB:         opsDB,
		pipelineNames: names,
	}
}

func (m HistoryModel) Init() tea.Cmd {
	return tea.Batch(
		m.spinner.Init(),
		m.loadHistory(),
	)
}

func (m HistoryModel) loadHistory() tea.Cmd {
	return func() tea.Msg {
		execs, err := m.opsDB.ListExecutions("", "", "")
		if err != nil {
			return historyLoadedMsg(nil)
		}
		return historyLoadedMsg(execs)
	}
}

func (m HistoryModel) Update(msg tea.Msg) (HistoryModel, tea.Cmd) {
	switch msg := msg.(type) {
	case historyLoadedMsg:
		m.executions = []ops.Execution(msg)
		items := make([]tui.ListItem, len(m.executions))
		for i, e := range m.executions {
			icon := "●"
			switch e.Status {
			case ops.ExecSuccess:
				icon = "✓"
			case ops.ExecFailure:
				icon = "✗"
			case ops.ExecPartial:
				icon = "~"
			}
			name := e.PipelineID
			if n, ok := m.pipelineNames[e.PipelineID]; ok {
				name = n
			}
			dur := ""
			if e.DurationMs != nil {
				dur = fmt.Sprintf("%dms", *e.DurationMs)
			}
			items[i] = tui.ListItem{
				Title:       fmt.Sprintf("%s %s", icon, name),
				Description: fmt.Sprintf("%s — %s — %s", string(e.Status), dur, e.StartedAt.Format("2006-01-02 15:04:05")),
				Value:       e,
			}
		}
		m.list.SetItems(items)
		m.state = historyList
		return m, nil

	case tea.KeyMsg:
		switch m.state {
		case historyList:
			switch msg.String() {
			case "r":
				m.state = historyLoading
				m.spinner = tui.NewSpinner("Loading history...")
				return m, tea.Batch(m.spinner.Init(), m.loadHistory())
			case "enter":
				if item := m.list.SelectedItem(); item != nil {
					e := item.Value.(ops.Execution)
					m.detail = formatExecution(e)
					m.state = historyDetail
					m.scrollOff = 0
				}
				return m, nil
			}
		case historyDetail:
			switch msg.String() {
			case "j", "down":
				m.scrollOff++
			case "k", "up":
				if m.scrollOff > 0 {
					m.scrollOff--
				}
			}
			return m, nil
		}
	}

	// Delegate to sub-components
	var cmd tea.Cmd
	switch m.state {
	case historyLoading:
		var spinnerModel tea.Model
		spinnerModel, cmd = m.spinner.Update(msg)
		m.spinner = spinnerModel.(tui.SpinnerModel)
	case historyList:
		var listModel tea.Model
		listModel, cmd = m.list.Update(msg)
		m.list = listModel.(tui.FilteredListModel)
	}
	return m, cmd
}

// HandleBack retrocede un nivel. Retorna true si ya en estado base.
func (m *HistoryModel) HandleBack() bool {
	switch m.state {
	case historyDetail:
		m.state = historyList
		return false
	default:
		return true
	}
}

func (m HistoryModel) View() string {
	switch m.state {
	case historyLoading:
		return m.spinner.View()
	case historyList:
		if len(m.executions) == 0 {
			return m.styles.Muted.Render("No executions found. Launch a pipeline first.")
		}
		help := m.styles.Muted.Render("  Enter: details │ r: refresh │ /: filter")
		return m.list.View() + "\n" + help
	case historyDetail:
		return m.renderDetail()
	}
	return ""
}

func (m HistoryModel) renderDetail() string {
	lines := splitLines(m.detail)
	maxLines := 20
	if m.scrollOff >= len(lines) {
		m.scrollOff = max(0, len(lines)-1)
	}
	end := min(m.scrollOff+maxLines, len(lines))
	visible := lines[m.scrollOff:end]

	header := m.styles.Header.Render("Execution Detail")
	content := lipgloss.JoinVertical(lipgloss.Left, visible...)
	help := m.styles.Muted.Render("  j/k: scroll │ Esc: back")

	return header + "\n" + content + "\n" + help
}

func formatExecution(e ops.Execution) string {
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("ID:        %s\n", e.ID))
	sb.WriteString(fmt.Sprintf("Pipeline:  %s\n", e.PipelineID))
	sb.WriteString(fmt.Sprintf("Status:    %s\n", e.Status))
	sb.WriteString(fmt.Sprintf("Started:   %s\n", e.StartedAt.Format("2006-01-02 15:04:05")))
	if e.EndedAt != nil {
		sb.WriteString(fmt.Sprintf("Ended:     %s\n", e.EndedAt.Format("2006-01-02 15:04:05")))
	}
	if e.DurationMs != nil {
		sb.WriteString(fmt.Sprintf("Duration:  %dms\n", *e.DurationMs))
	}
	if e.RecordsIn != nil {
		sb.WriteString(fmt.Sprintf("Records In:  %d\n", *e.RecordsIn))
	}
	if e.RecordsOut != nil {
		sb.WriteString(fmt.Sprintf("Records Out: %d\n", *e.RecordsOut))
	}
	if e.Error != "" {
		sb.WriteString(fmt.Sprintf("\n--- Error ---\n%s\n", e.Error))
	}
	if len(e.Metrics) > 0 {
		sb.WriteString("\n--- Metrics ---\n")
		b, _ := json.MarshalIndent(e.Metrics, "", "  ")
		sb.WriteString(string(b))
		sb.WriteString("\n")
	}
	return sb.String()
}