package catalog

import (
	"context"
	"io"

	"github.com/a-h/templ"

	"backend/internal/web/ui"
)

// Example is a single rendered component variant with a templ call annotation.
type Example struct {
	Title   string
	Preview templ.Component
	Snippet string
}

type anyComponent = templ.Component

func badgeExamples() []Example {
	return []Example{
		{
			Title: "Info",
			Preview: ui.Badge(ui.BadgeProps{
				Label:   "Info",
				Variant: ui.BadgeVariantInfo,
			}),
			Snippet: `@ui.Badge(ui.BadgeProps{Label: "Info", Variant: ui.BadgeVariantInfo})`,
		},
		{
			Title: "Warning",
			Preview: ui.Badge(ui.BadgeProps{
				Label:   "Warning",
				Variant: ui.BadgeVariantWarning,
			}),
			Snippet: `@ui.Badge(ui.BadgeProps{Label: "Warning", Variant: ui.BadgeVariantWarning})`,
		},
		{
			Title: "Success",
			Preview: ui.Badge(ui.BadgeProps{
				Label:   "Success",
				Variant: ui.BadgeVariantSuccess,
			}),
			Snippet: `@ui.Badge(ui.BadgeProps{Label: "Success", Variant: ui.BadgeVariantSuccess})`,
		},
		{
			Title: "Danger",
			Preview: ui.Badge(ui.BadgeProps{
				Label:   "Danger",
				Variant: ui.BadgeVariantDanger,
			}),
			Snippet: `@ui.Badge(ui.BadgeProps{Label: "Danger", Variant: ui.BadgeVariantDanger})`,
		},
		{
			Title: "Primary",
			Preview: ui.Badge(ui.BadgeProps{
				Label:   "Primary",
				Variant: ui.BadgeVariantPrimary,
			}),
			Snippet: `@ui.Badge(ui.BadgeProps{Label: "Primary", Variant: ui.BadgeVariantPrimary})`,
		},
	}
}

func buttonExamples() []Example {
	return []Example{
		{
			Title: "Solid / Default",
			Preview: ui.Button(ui.ButtonProps{
				Label:   "Create project",
				Variant: ui.ButtonVariantDefault,
				Tone:    ui.ButtonToneSolid,
				Size:    ui.SizeMD,
				Type:    "button",
			}),
			Snippet: `@ui.Button(ui.ButtonProps{
    Label:   "Create project",
    Variant: ui.ButtonVariantDefault,
    Tone:    ui.ButtonToneSolid,
    Size:    ui.SizeMD,
    Type:    "button",
})`,
		},
		{
			Title: "Solid / Danger",
			Preview: ui.Button(ui.ButtonProps{
				Label:   "Delete",
				Variant: ui.ButtonVariantDanger,
				Tone:    ui.ButtonToneSolid,
				Size:    ui.SizeMD,
				Type:    "button",
			}),
			Snippet: `@ui.Button(ui.ButtonProps{
    Label:   "Delete",
    Variant: ui.ButtonVariantDanger,
    Tone:    ui.ButtonToneSolid,
    Size:    ui.SizeMD,
    Type:    "button",
})`,
		},
		{
			Title: "Soft / Neutral",
			Preview: ui.Button(ui.ButtonProps{
				Label:   "Cancel",
				Variant: ui.ButtonVariantNeutral,
				Tone:    ui.ButtonToneSoft,
				Size:    ui.SizeMD,
				Type:    "button",
			}),
			Snippet: `@ui.Button(ui.ButtonProps{
    Label:   "Cancel",
    Variant: ui.ButtonVariantNeutral,
    Tone:    ui.ButtonToneSoft,
    Size:    ui.SizeMD,
    Type:    "button",
})`,
		},
		{
			Title: "Ghost",
			Preview: ui.Button(ui.ButtonProps{
				Label:   "Learn more",
				Variant: ui.ButtonVariantGhost,
				Size:    ui.SizeMD,
				Type:    "button",
			}),
			Snippet: `@ui.Button(ui.ButtonProps{
    Label:   "Learn more",
    Variant: ui.ButtonVariantGhost,
    Size:    ui.SizeMD,
    Type:    "button",
})`,
		},
	}
}

func cardExamples() []Example {
	return []Example{
		{
			Title: "Card with header, body, and footer",
			Preview: ui.Card(ui.CardProps{
				Header: textBody("Card Header"),
				Body:   textBody("Card body content goes here."),
				Footer: textBody("Card Footer"),
			}),
			Snippet: `@ui.Card(ui.CardProps{
    Header: headerComponent,
    Body:   bodyComponent,
    Footer: footerComponent,
})`,
		},
	}
}

func emptyStateExamples() []Example {
	return []Example{
		{
			Title: "Empty list",
			Preview: ui.EmptyState(ui.EmptyStateProps{
				Title:       "Nothing here yet",
				Description: "Add your first item to get started.",
				Icon:        ui.UIIcon("grid3x3"),
				Action: ui.Button(ui.ButtonProps{
					Label:   "Add item",
					Variant: ui.ButtonVariantDefault,
					Tone:    ui.ButtonToneSolid,
					Size:    ui.SizeMD,
					Type:    "button",
					Icon:    "plus",
				}),
			}),
			Snippet: `@ui.EmptyState(ui.EmptyStateProps{
    Title:       "Nothing here yet",
    Description: "Add your first item to get started.",
    Icon:        ui.UIIcon("grid3x3"),
    Action:      ui.Button(...),
})`,
		},
	}
}

func formFieldExamples() []Example {
	return []Example{
		{
			Title: "Field with label, hint, and error",
			Preview: ui.FormField(ui.FormFieldProps{
				Label: "Project name",
				For:   "catalog-name",
				Field: ui.Input(ui.InputProps{
					ID:          "catalog-name",
					Name:        "name",
					Placeholder: "Enter a name",
					Type:        "text",
				}),
				Hint:  "Enter a value between 1 and 100.",
				Error: "This field is required.",
			}),
			Snippet: `@ui.FormField(ui.FormFieldProps{
    Label: "Project name",
    For:   "catalog-name",
    Field: ui.Input(ui.InputProps{...}),
    Hint:  "Enter a value between 1 and 100.",
    Error: "This field is required.",
})`,
		},
	}
}

func iconButtonExamples() []Example {
	return []Example{
		{
			Title: "Ghost / Neutral (plus icon)",
			Preview: ui.IconButton(ui.IconButtonProps{
				Label:   "Add item",
				Icon:    "plus",
				Variant: ui.IconButtonVariantNeutral,
				Tone:    ui.IconButtonToneGhost,
				Type:    "button",
			}),
			Snippet: `@ui.IconButton(ui.IconButtonProps{
    Label:   "Add item",
    Icon:    "plus",
    Variant: ui.IconButtonVariantNeutral,
    Tone:    ui.IconButtonToneGhost,
    Type:    "button",
})`,
		},
		{
			Title: "Solid / Danger (trash icon)",
			Preview: ui.IconButton(ui.IconButtonProps{
				Label:   "Delete item",
				Icon:    "trash",
				Variant: ui.IconButtonVariantDanger,
				Tone:    ui.IconButtonToneSolid,
				Type:    "button",
			}),
			Snippet: `@ui.IconButton(ui.IconButtonProps{
    Label:   "Delete item",
    Icon:    "trash",
    Variant: ui.IconButtonVariantDanger,
    Tone:    ui.IconButtonToneSolid,
    Type:    "button",
})`,
		},
	}
}

func inputExamples() []Example {
	return []Example{
		{
			Title: "Text input",
			Preview: ui.Input(ui.InputProps{
				Name:        "name",
				Placeholder: "Enter text here",
				Type:        "text",
			}),
			Snippet: `@ui.Input(ui.InputProps{
    Name:        "name",
    Placeholder: "Enter text here",
    Type:        "text",
})`,
		},
		{
			Title: "Email input",
			Preview: ui.Input(ui.InputProps{
				Name:        "email",
				Placeholder: "you@example.com",
				Type:        "email",
			}),
			Snippet: `@ui.Input(ui.InputProps{
    Name:        "email",
    Placeholder: "you@example.com",
    Type:        "email",
})`,
		},
	}
}

func modalExamples() []Example {
	return []Example{
		{
			Title: "Modal panel (no backdrop)",
			// Render only the panel div — not the full Modal component with backdrop.
			// Pitfall 7: ui-modal-backdrop is position:fixed and would overlay the catalog page.
			Preview: componentFunc(func(ctx context.Context, w io.Writer) error {
				_, err := io.WriteString(w, `<div class="ui-modal-panel" style="position:relative;max-width:32rem;margin:0 auto;">`)
				if err != nil {
					return err
				}
				if err := renderComponents(ctx, w,
					textBody(`<div class="ui-modal-header"><h2>Confirm action</h2></div>`),
					textBody(`<div class="ui-modal-body"><p>Are you sure you want to proceed?</p></div>`),
					textBody(`<div class="ui-modal-actions">`),
				); err != nil {
					return err
				}
				if err := ui.Button(ui.ButtonProps{
					Label:   "Cancel",
					Variant: ui.ButtonVariantNeutral,
					Tone:    ui.ButtonToneSoft,
					Size:    ui.SizeMD,
					Type:    "button",
				}).Render(ctx, w); err != nil {
					return err
				}
				if err := ui.Button(ui.ButtonProps{
					Label:   "Confirm",
					Variant: ui.ButtonVariantDefault,
					Tone:    ui.ButtonToneSolid,
					Size:    ui.SizeMD,
					Type:    "button",
				}).Render(ctx, w); err != nil {
					return err
				}
				_, err = io.WriteString(w, `</div></div>`)
				return err
			}),
			Snippet: `@ui.Modal(ui.ModalProps{
    Title:   "Confirm action",
    Body:    bodyContent,
    Actions: actionButtons,
})`,
		},
	}
}

func selectExamples() []Example {
	return []Example{
		{
			Title: "Single select",
			Preview: ui.Select(ui.SelectProps{
				Name:        "status",
				Placeholder: "Select a status",
				Value:       "in-progress",
				Options: []ui.SelectOption{
					{Value: "todo", Label: "To do"},
					{Value: "in-progress", Label: "In progress"},
					{Value: "done", Label: "Done"},
				},
			}),
			Snippet: `@ui.Select(ui.SelectProps{
    Name:        "status",
    Placeholder: "Select a status",
    Value:       "in-progress",
    Options: []ui.SelectOption{
        {Value: "todo", Label: "To do"},
        {Value: "in-progress", Label: "In progress"},
        {Value: "done", Label: "Done"},
    },
})`,
		},
	}
}

func tableExamples() []Example {
	return []Example{
		{
			Title: "Data table",
			Preview: ui.Table(ui.TableProps{
				Head: textBody(`<tr><th style="padding:0.75rem 1rem;text-align:left;font-size:0.75rem;font-weight:600;text-transform:uppercase;letter-spacing:0.05em;">Name</th><th style="padding:0.75rem 1rem;text-align:left;font-size:0.75rem;font-weight:600;text-transform:uppercase;letter-spacing:0.05em;">Status</th></tr>`),
				Body: textBody(`<tr><td style="padding:0.75rem 1rem;">Example Project</td><td style="padding:0.75rem 1rem;">In progress</td></tr><tr><td style="padding:0.75rem 1rem;">Another Project</td><td style="padding:0.75rem 1rem;">Done</td></tr>`),
			}),
			Snippet: `@ui.Table(ui.TableProps{
    Head: tableHead,
    Body: tableBody,
})`,
		},
	}
}

func textareaExamples() []Example {
	return []Example{
		{
			Title: "Textarea with placeholder",
			Preview: ui.Textarea(ui.TextareaProps{
				Name:        "description",
				Placeholder: "Enter a description...",
				Rows:        4,
			}),
			Snippet: `@ui.Textarea(ui.TextareaProps{
    Name:        "description",
    Placeholder: "Enter a description...",
    Rows:        4,
})`,
		},
	}
}

func componentFunc(fn func(context.Context, io.Writer) error) templ.Component {
	return templ.ComponentFunc(fn)
}

func textBody(text string) templ.Component {
	return templ.ComponentFunc(func(_ context.Context, w io.Writer) error {
		_, err := io.WriteString(w, text)
		return err
	})
}

func renderComponents(ctx context.Context, w io.Writer, components ...templ.Component) error {
	for _, c := range components {
		if err := c.Render(ctx, w); err != nil {
			return err
		}
	}
	return nil
}