import { createTheme } from '@mui/material/styles';
import type { Shadows } from '@mui/material/styles';
import { getCssVar, CSS_VAR_FALLBACKS } from './css-vars';

/**
 * MUI adapter over the CSS-variable token file (src/styles/theme.css).
 * Mirrors shoc-frontend-new dev src/lib/theme/mui-theme.ts (ADR 0003).
 * Token changes are values-only edits in theme.css — never here.
 */

declare module '@mui/material/styles' {
  interface Palette {
    header: Palette['primary'];
  }
  interface PaletteOptions {
    header?: PaletteOptions['primary'];
  }
}

const v = (name: string, fallback: string) => getCssVar(name, fallback);

const primary = v('--primary', CSS_VAR_FALLBACKS.primary);
const primaryHover = v('--primary-hover', CSS_VAR_FALLBACKS.primaryHover);
const primaryForeground = v('--primary-foreground', CSS_VAR_FALLBACKS.primaryForeground);
const destructive = v('--destructive', CSS_VAR_FALLBACKS.destructive);
const success = v('--success', CSS_VAR_FALLBACKS.success);
const warning = v('--warning', CSS_VAR_FALLBACKS.warning);
const background = v('--background', CSS_VAR_FALLBACKS.background);
const foreground = v('--foreground', CSS_VAR_FALLBACKS.foreground);
const border = v('--border', CSS_VAR_FALLBACKS.border);
const muted = v('--muted', CSS_VAR_FALLBACKS.muted);
const mutedForeground = v('--muted-foreground', CSS_VAR_FALLBACKS.mutedForeground);
const inputBackground = v('--input-background', CSS_VAR_FALLBACKS.inputBackground);
const ring = v('--ring', CSS_VAR_FALLBACKS.ring);
const bgPage = v('--color-bg-page', CSS_VAR_FALLBACKS.bgPage);
const radius = parseInt(v('--radius', `${CSS_VAR_FALLBACKS.radius}px`), 10);
const headerEnd = v('--color-header-bg-end', CSS_VAR_FALLBACKS.headerEnd);
const headerText = v('--color-header-text', CSS_VAR_FALLBACKS.headerText);

const shadowSm = v('--shadow-sm', '0 1px 3px rgba(22, 30, 56, 0.06), 0 1px 2px rgba(22, 30, 56, 0.04)');
const shadowMd = v('--shadow-md', '0 4px 6px -1px rgba(22, 30, 56, 0.08), 0 2px 4px -2px rgba(22, 30, 56, 0.06)');
const shadowLg = v('--shadow-lg', '0 10px 15px -3px rgba(22, 30, 56, 0.1), 0 4px 6px -4px rgba(22, 30, 56, 0.08)');

const fontSans = '"DM Sans", ui-sans-serif, system-ui, sans-serif';
const fontDisplay = '"Montserrat", ui-sans-serif, system-ui, sans-serif';

// MUI's 25-slot elevation tuple, fully overridden: 0=none, 1–2=sm, 3–5=md, 6+=lg.
const shadows = [
  'none',
  shadowSm,
  shadowSm,
  shadowMd,
  shadowMd,
  shadowMd,
  ...Array<string>(19).fill(shadowLg),
] as Shadows;

export const muiTheme = createTheme({
  palette: {
    mode: 'light',
    primary: {
      main: primary,
      dark: primaryHover,
      contrastText: primaryForeground,
    },
    // Repurposed as the muted/neutral swatch (SHOC convention), not a brand color.
    secondary: {
      main: muted,
      contrastText: foreground,
    },
    error: {
      main: destructive,
      contrastText: '#ffffff',
    },
    success: {
      main: success,
      contrastText: '#ffffff',
    },
    warning: {
      main: warning,
      contrastText: '#ffffff',
    },
    background: {
      default: bgPage,
      paper: background,
    },
    text: {
      primary: foreground,
      secondary: mutedForeground,
    },
    divider: border,
    header: {
      main: headerEnd,
      contrastText: headerText,
    },
  },

  typography: {
    fontFamily: fontSans,
    fontSize: 14,
    fontWeightRegular: 400,
    fontWeightMedium: 500,
    fontWeightBold: 600,
    h1: { fontFamily: fontDisplay, fontWeight: 800, fontSize: '1.75rem', lineHeight: 1.25 },
    h2: { fontFamily: fontDisplay, fontWeight: 700, fontSize: '1.375rem', lineHeight: 1.25 },
    h3: { fontFamily: fontDisplay, fontWeight: 600, fontSize: '1.125rem', lineHeight: 1.25 },
    h4: { fontFamily: fontDisplay, fontWeight: 600, fontSize: '1rem', lineHeight: 1.25 },
    h5: { fontFamily: fontDisplay, fontWeight: 600, fontSize: '0.875rem', lineHeight: 1.25 },
    h6: { fontFamily: fontDisplay, fontWeight: 600, fontSize: '0.8125rem', lineHeight: 1.25 },
    subtitle1: { fontWeight: 600, fontSize: '1rem' },
    subtitle2: { fontWeight: 500, fontSize: '0.875rem', color: mutedForeground },
    body1: { fontSize: '0.875rem', lineHeight: 1.5 },
    body2: { fontSize: '0.8125rem', lineHeight: 1.5, color: mutedForeground },
    caption: { fontSize: '0.75rem', color: mutedForeground },
    button: { textTransform: 'none' as const, fontWeight: 600, fontSize: '0.875rem' },
    overline: {
      fontSize: '0.6875rem',
      fontWeight: 600,
      letterSpacing: '0.08em',
      textTransform: 'uppercase' as const,
      color: mutedForeground,
    },
  },

  shape: {
    borderRadius: radius,
  },

  shadows,

  components: {
    MuiCssBaseline: {
      styleOverrides: {
        body: {
          fontSize: 14,
          backgroundColor: bgPage,
          color: foreground,
        },
      },
    },

    MuiButton: {
      defaultProps: {
        disableElevation: true,
      },
      styleOverrides: {
        root: {
          borderRadius: 'var(--radius-md)',
          textTransform: 'none' as const,
          fontWeight: 600,
          fontSize: '0.875rem',
          transition: 'background-color var(--duration-fast) var(--ease-default), box-shadow var(--duration-fast) var(--ease-default)',
          '&:focus-visible': {
            outline: `2px solid ${ring}`,
            outlineOffset: 2,
          },
          // MUI v9: containedPrimary slot removed — class selector instead
          '&.MuiButton-containedPrimary:hover': {
            backgroundColor: primaryHover,
          },
        },
        outlined: {
          borderColor: border,
          '&:hover': {
            borderColor: 'var(--border-hover)',
            backgroundColor: 'var(--secondary)',
          },
        },
      },
    },

    MuiTextField: {
      defaultProps: {
        size: 'small' as const,
      },
    },

    MuiOutlinedInput: {
      styleOverrides: {
        root: {
          backgroundColor: inputBackground,
          borderRadius: 'var(--radius-md)',
          '& .MuiOutlinedInput-notchedOutline': {
            borderColor: border,
          },
          '&:hover .MuiOutlinedInput-notchedOutline': {
            borderColor: 'var(--border-hover)',
          },
          '&.Mui-focused': {
            boxShadow: `0 0 0 3px color-mix(in srgb, ${ring} 25%, transparent)`,
          },
          '&.Mui-focused .MuiOutlinedInput-notchedOutline': {
            borderColor: ring,
            borderWidth: 2,
          },
        },
        input: {
          padding: '8.5px 13px',
          fontSize: '0.875rem',
          '&.MuiOutlinedInput-inputAdornedEnd': {
            paddingRight: 40,
          },
        },
      },
    },

    MuiTableCell: {
      styleOverrides: {
        root: {
          fontSize: '0.875rem',
          borderColor: border,
          padding: '10px 16px',
        },
        head: {
          fontWeight: 600,
          backgroundColor: 'var(--color-bg-muted)',
          color: foreground,
        },
      },
    },

    MuiTableRow: {
      styleOverrides: {
        root: {
          '&:last-child .MuiTableCell-root': {
            borderBottom: 0,
          },
        },
      },
    },

    MuiChip: {
      styleOverrides: {
        root: {
          borderRadius: 'var(--radius-sm)',
          fontWeight: 500,
          fontSize: '0.75rem',
        },
        outlined: {
          borderColor: border,
        },
      },
    },

    MuiPaper: {
      defaultProps: {
        elevation: 0,
      },
      styleOverrides: {
        root: {
          backgroundImage: 'none',
          borderRadius: radius,
        },
        outlined: {
          borderColor: border,
        },
      },
    },

    MuiDialog: {
      styleOverrides: {
        paper: {
          borderRadius: 'var(--radius-xl)',
          boxShadow: shadowLg,
        },
      },
    },

    MuiAlert: {
      styleOverrides: {
        root: {
          borderRadius: 'var(--radius-md)',
          fontSize: '0.875rem',
          // MUI v9: standard* slots removed — class selectors instead
          '&.MuiAlert-standardSuccess': {
            backgroundColor: 'var(--status-completed-bg)',
            color: 'var(--status-completed-text)',
          },
          '&.MuiAlert-standardError': {
            backgroundColor: 'var(--doc-no-bg)',
            color: 'var(--doc-no-text)',
          },
          '&.MuiAlert-standardWarning': {
            backgroundColor: 'var(--status-pending-bg)',
            color: 'var(--status-pending-text)',
          },
          '&.MuiAlert-standardInfo': {
            backgroundColor: 'var(--color-primary-tint)',
            color: 'var(--sidebar-accent-foreground)',
          },
        },
      },
    },
  },
});