package views

import (
	"fmt"
	"strings"

	ops "fn-registry/fn_operations"
	"fn-registry/registry"

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

type pipelinesState int

const (
	pipelinesLoading pipelinesState = iota
	pipelinesList
	pipelinesRunning
	pipelinesOutput
)

type pipelinesLoadedMsg []registry.Function
type pipelineFinishedMsg RunResult

// PipelinesModel lists and launches pipelines.
type PipelinesModel struct {
	state        pipelinesState
	list         tui.FilteredListModel
	spinner      tui.SpinnerModel
	styles       tui.Styles
	pipelines    []registry.Function
	output       string
	lastResult   *RunResult
	scrollOff    int
	err          error
	registryDB   *registry.DB
	opsDB        *ops.DB
	registryRoot string
}

// NewPipelinesModel creates a new pipelines view.
func NewPipelinesModel(styles tui.Styles, regDB *registry.DB, opsDB *ops.DB, root string) PipelinesModel {
	return PipelinesModel{
		state:        pipelinesLoading,
		list:         tui.NewFilteredList(nil, "Filter pipelines..."),
		spinner:      tui.NewSpinner("Loading pipelines..."),
		styles:       styles,
		registryDB:   regDB,
		opsDB:        opsDB,
		registryRoot: root,
	}
}

func (m PipelinesModel) Init() tea.Cmd {
	return tea.Batch(
		m.spinner.Init(),
		m.loadPipelines(),
	)
}

func (m PipelinesModel) loadPipelines() tea.Cmd {
	return func() tea.Msg {
		fns, err := m.registryDB.SearchFunctions("", registry.KindPipeline, "", "", "")
		if err != nil {
			return pipelinesLoadedMsg(nil)
		}
		return pipelinesLoadedMsg(fns)
	}
}

func (m PipelinesModel) Update(msg tea.Msg) (PipelinesModel, tea.Cmd) {
	switch msg := msg.(type) {
	case pipelinesLoadedMsg:
		m.pipelines = []registry.Function(msg)
		items := make([]tui.ListItem, len(m.pipelines))
		for i, p := range m.pipelines {
			items[i] = tui.ListItem{
				Title:       p.Name,
				Description: fmt.Sprintf("%s — %s", p.Domain, truncate(p.Description, 60)),
				Value:       p,
			}
		}
		m.list.SetItems(items)
		m.state = pipelinesList
		return m, nil

	case pipelineFinishedMsg:
		result := RunResult(msg)
		m.lastResult = &result
		// Build output
		var sb strings.Builder
		if result.Status == ops.ExecSuccess {
			sb.WriteString("[OK] ")
		} else {
			sb.WriteString("[FAIL] ")
		}
		sb.WriteString(fmt.Sprintf("Pipeline: %s\n", result.PipelineID))
		sb.WriteString(fmt.Sprintf("Execution: %s\n", result.ExecID))
		sb.WriteString(fmt.Sprintf("Duration: %dms\n", result.DurationMs))
		sb.WriteString("\n--- stdout ---\n")
		if result.Stdout != "" {
			sb.WriteString(result.Stdout)
		} else {
			sb.WriteString("(empty)")
		}
		if result.Stderr != "" {
			sb.WriteString("\n--- stderr ---\n")
			sb.WriteString(result.Stderr)
		}
		if result.Err != nil {
			sb.WriteString(fmt.Sprintf("\n--- error ---\n%v", result.Err))
		}
		m.output = sb.String()
		m.state = pipelinesOutput
		m.scrollOff = 0
		return m, nil

	case tea.KeyMsg:
		switch m.state {
		case pipelinesList:
			switch msg.String() {
			case "r":
				m.state = pipelinesLoading
				m.spinner = tui.NewSpinner("Loading pipelines...")
				return m, tea.Batch(m.spinner.Init(), m.loadPipelines())
			case "enter":
				if item := m.list.SelectedItem(); item != nil {
					fn := item.Value.(registry.Function)
					m.state = pipelinesRunning
					m.spinner = tui.NewSpinner(fmt.Sprintf("Running %s...", fn.Name))
					return m, tea.Batch(m.spinner.Init(), m.runPipelineCmd(&fn))
				}
			}
		case pipelinesOutput:
			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 pipelinesLoading, pipelinesRunning:
		var spinnerModel tea.Model
		spinnerModel, cmd = m.spinner.Update(msg)
		m.spinner = spinnerModel.(tui.SpinnerModel)
	case pipelinesList:
		var listModel tea.Model
		listModel, cmd = m.list.Update(msg)
		m.list = listModel.(tui.FilteredListModel)
	}
	return m, cmd
}

func (m PipelinesModel) runPipelineCmd(fn *registry.Function) tea.Cmd {
	regRoot := m.registryRoot
	opsDB := m.opsDB
	fnCopy := *fn
	return func() tea.Msg {
		result := RunPipeline(&fnCopy, regRoot, opsDB)
		return pipelineFinishedMsg(result)
	}
}

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

func (m PipelinesModel) View() string {
	switch m.state {
	case pipelinesLoading:
		return m.spinner.View()
	case pipelinesList:
		if len(m.pipelines) == 0 {
			return m.styles.Muted.Render("No pipelines found. Press 'r' to refresh.")
		}
		help := m.styles.Muted.Render("  Enter: launch │ r: refresh │ /: filter")
		return m.list.View() + "\n" + help
	case pipelinesRunning:
		return m.spinner.View()
	case pipelinesOutput:
		return m.renderOutput()
	}
	return ""
}

func (m PipelinesModel) renderOutput() string {
	lines := splitLines(m.output)
	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("Pipeline Output")
	content := lipgloss.JoinVertical(lipgloss.Left, visible...)
	help := m.styles.Muted.Render("  j/k: scroll │ Esc: back")

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

func splitLines(s string) []string {
	if s == "" {
		return []string{"(empty)"}
	}
	lines := strings.Split(s, "\n")
	if len(lines) == 0 {
		return []string{"(empty)"}
	}
	return lines
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n-3] + "..."
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}